Anyone tried the 716.640 6 Speed Manual trans from a 220/270CDi in their conversions...?

--Bell-housing fits, 60x engines but needs custom flywheel apparently, uses std 270 CDi plate and a Sachs cover....

Wiring for W123 reverse-light is grey/yellow-tracer and black, --forget the tracer colour.

The thick Purples with white tracer are the start-inhibit/safety switch....

Doubt it needs the custom fw, probably just the dual mass...

Just going by what Muuris was saying over on the 'Dark-Side'....;)

My BIL's car (info here) has a 1984 190E tranny, which should be 717.411, however the gear ratios are surprisingly hard to locate. I finally found them in a Haynes manual - but the Haynes says the data is for a .410 tranny. Gotta be a typo on something here. The MB TDM shows the .411 overdrive as 0.777, which supports the Hanyes data, but who knows if the ratios below for gears 1-3 are correct:

1st = 3.91
2nd = 2.17
3rd = 1.37
4th = 1.00
5th = 0.777

Anyone have a good source for identifying MB transmission gear ratios?

:detective:

717.411----------------3.91, 2.32, 1.42, 1.00, 0.78

This is the info I have. I am pretty sure I got the ratios from a friend of mine who knows MB transmission like the palm of his hand. He lurks here but rarely post's

gsxr,

What would you do?

When I swap the diffs would you swap diff yokes? Using the method you told me about.

OR

Keep the smaller yoke on the new diff and get a complete 300e driveshaft?

I am concerned about the smaller flex disks on the 300e/260e stuff. I do currently have a smaller disk at the transmission end, remember that pricey custom driveshaft I had made?:eek:

So I'd like a taller final drive in the '87 300TD, runs around 3000rpm @ 78mph, would love to drop that if I had an overdrive. Should pull fine up there at closer to 2500rpm.

This is of course the stock 2.65:1 with 1:1 final, for the same top RPM in a .78:1 overdrive you're looking at a 3.39:1 diff.

To drop to my goal of 2500rpm at 78mph (where I set my CC), would mean around a 2.80:1 rear screw, I'd expect that 2.89:1 is a more common diff ratio, is there one available for these cars?

Well, ideally I would swap the diff input flange, but I'd try to borrow (or buy) the tool to do it right. My second choice would be to leave it alone and use a complete 300E driveshaft (which are dirt cheap), as long as you don't intend to increase power level beyond what the stock pump can deliver maxed out. Last choice would be to swap the flange/yoke using the "mark the nut" method.

If you use 300E-size flex discs, make sure they are both the "firm" type, not the "soft" type. The 300E (and 124.128) use a soft front disc and firm rear disc. Click here to view a photo of the soft/front version, click here for a photo of the rear/firm type. Note the difference in design. The 1987 300D (and 400E/500E) use firm discs at both ends.


On a side note, is anyone using the factory-correct engine mounts with the manual transmission, as specified in the EPC? The Euro-spec 124.128 with 717.437 tranny uses different engine mounts than the automatic. Auto tranny engine mounts are 201-240-42-17 (non-taxi) or 124-240-19-17 (taxi version). Manual tranny engine mounts are 124-240-17-17 (non-taxi) or 201-240-41-17.

For reference, the USA-spec 124.133 uses 124-240-19-17 mounts, and the USA-spec 124.128 uses 201-240-42-17 mounts. Although the WhirledPack catalogs usually cross-reference these all to the same mount (124-240-22-17 / 87855A, apparently used on the early 90's 300E/CE/TE only), they are NOT the same, and you can get the real ones from MB (for a small fortune). I've noticed the x-ref version doesn't seem to last very long but I've never been willing to shell out over $100/ea to try the "real" ones. Maybe next time. Even stranger, the 124.131 uses a different mount for left & right! (201-240-52-17 left, 124-240-19-17 right). Never noticed that before...

:stuart:

I'm confused. How would you get an overdrive? Are you talking about doing a 5-speed manual swap? The OD ratio varies with each. Anyway:

If you want to drop from 3000 to 2500, you need a final drive ratio of 2.21 (approx). The only factory diff near that is from the US-spec 400E at 2.24, but of course this would be way tall for 1st gear, and it's the bigger/heavier 210mm carrier.

To achieve near 2.21 with an OD, a 2.87 gear ratio (which is closest to your desired 2.89) in the 185mm size, with a 0.777 OD fifth gear, would povide a 2.23 final drive. As you can see in my diff spreadsheet, 2.87 is the only ratio you'll find in that range in the correct housing. Next taller is 2.65 (what you have now), next lower is 3.07. You can get a 2.87 ASD from a 124.131 with optional ASD, to get LSD. There's a couple in VA for ~$300.

You really don't want a 210mm housing, which come with a 2.82 gearset, not 2.87. The larger housing would also require getting a rear diff cover from a .032/.052/.092/etc and possibly some flange swapping. No need for it unless you're blowing up the 185mm units, which would probably mean >300hp.

Personally, I'd opt for a 3.07 with overdrive (2.30 - 2.56 final drive, depending on the 5th gear ratio) as a better compromise. For more ooomph off the line, a 3.27 would be fun, and the OD would keep final drive to 2.45-2.72.

:kid:

You got that right :icon_confused::blink:

I fail to understand how this 3.29 rear diff I have locks the hubs. I took the cover off and drained it, then pulled the clip and pulled a flange(what is it called?) off. Just looks like a bearing where that lock/clutch(?) is at.

gsxr??

You mean, how does the ASD work? The external ring cylinders push the flange outward when hydraulic pressure is applied... this converts the hydraulic system pressure into pressure on the internal clutch pack, effectively locking it 100% (with new clutches). The ring cylinder pushes on the bearing which is mounted on the ASD axle flange. Assuming you don't plan to connect the hydraulic lines to anything, and/or you plan to convert to the plain axle flanges from the original diff, that doesn't matter. You may want to look at my photos here from my ASD-->LSD conversion project. A more complete explanation of ASD & 4Matic operation is in this factory brochure.

:scooter:

Ok so the clutches are in those things that bolt to the side, sorry for the technical terms. It looks pretty straight forward to replace the clutches... am I missing something? It looks like you rebuilt the entire diff. I imagine the clutches are not cheap and HAVE to come from MB. What are you using to lock them? Some sort hand pump?

Can I use run of the mill sealant for the diff cover for now? Is that special MB stuff is for the pressure from the asd? You should charge people for the use of your website, except me naturally.

I can't really see the need for the full locking rear unless I had some crazy HP. Might be nice in the snow.

I got the 400e looked at today, just the muffler hitting a heat shield. So now I need to find out whats wrong with my SD's crank pulley then look at something odd in the front end of my TD. THEN I can get to the diff swap. :dizzy2:

No no no! The clutches are in the middle of the diff, inside the ring gear carrier. The thigns that bolt to the side are the hydraulic ring cylinders. Those ring cylinders are on/off... when hydraulic pressure is applied from the ASD or 4Matic system, the ring cylinders push the axle flange outward. This locks the internal clutch pack. But the ring cylinder is external to the diff, while the clutch pack is internal. Totally different items.



It is straightforward. Take apart the entire diff, replace clutches, re-assemble. It's just expensive and time consuming.



That is basically correct, except I did not replace any bearings, and did not touch the pinion other than to replace the seal (which I wouldn't recommend if it's dry - just leave it alone). The clutchs have to come from MB but you can get all the parts required for <$300 from parts dot com.



No, I removed the hydraulics completely and converted from ASD/4Matic to plain LSD. I have 35% max lock only from the internal clutch pack. That's it. Plain limited slip. The photos showing the ASD diff with hydraulics are the 'before'... that's what I started with, but after it was done the hydraulic ring cylinders were removed along with the longer axle flanges/stubs.



LOL! You can use other sealant, but I would highly recommend using blue Hylomar, which is what the MB stuff is. The MB sealant isn't that expensive though, about $20 for a big tube which will seal a bunch of diff covers. You could probably find an equivalent at your local NAPA though.




Exactly. That's why I didn't bother messing with hydraulics. I like the factory ASD (and 4Matic) systems but you can't retrofit ASD to a car that didn't come with it (at least, not without a massive amount of time & effort). It took me a year to find a 124.128 with ASD and heated seats that wasn't from the rust belt. The ASD is really nice on slick surfaces. Some folks have added hydraulics to manually engage it but that's really not needed for 99% of us.


:wheelchair:

Typical LSD clutch packs have a residual friction with no load, then with a load on the diff the natural tendency of the side-gears / spur gears when loaded is to push outward (to spread apart inside the carrier) which adds pressure to the clutch pack, resulting in additional friction/locking.